Homosexuals and lesbians will often say that people who love each other, no matter what their gender, should be allowed to marry each other. After all, they say, that's what heterosexual couples do. Why shouldn't homosexuals have the same rights? It makes sense, doesn't it? It does but not that much.
First of all, love is not the basis on which marriage is defined or justified. Marriage is defined by a public, legal commitment; and love is not a necessary component of the contract (though it is a good idea to love each other). Marriage is entered into by a mutual agreement that involves emotional and sexual faithfulness and the promise to raise children within its bounds. Of course, some heterosexual couples can't have children, and some adults marry knowing they will not have children. The issue is that marriage has always been the normal means by which children have been brought into the world. The marriage institution is supposed to provide a stable environment.
Second, if marriage is justified simply because two people love each other, then what do you do with two married couples who don't love each other, but the husband of one couple loves the wife of another? If the reason is raised that love is what determines that they can/should be married, then shouldn't they each dissolve their present marriages and marry each other? Or, are there other moral considerations involved that should be considered? Should marriages be formed and dissolved under such circumstances? How would this affect society as a whole?
Third, what about the collateral effect of redefining marriage and using "love" as the justification of legal bonding? Consider pedophiles. If a pedophile loves a young boy and the young boy loves the grown man, then shouldn't they be allowed to get married--if they are both mature enough for consent? After all, if love is the criteria that justifies two homosexuals or two lesbians getting married, then why can it not also be applied to pedophilia--or as the new term that has been proposed, "minor-attracted persons."
What about polygamy and polyandry? Would those who say homosexual marriage is okay as long as two people love each other--also advocate one man having many wives and one woman having many husbands as long as they love each other? It would seem that in order to be consistent they would have to.
Where does it stop? Just saying that love is what justifies homosexual marriage can also be used to justify other things. It is a dangerous argument--illogical--and is wrought with problems and pitfalls.